Originally Posted by crassius
I note that it may be the case that a larger gap could cause the spark to wait fractionally for the voltage to climb higher to jump the gap - in fact, a too large gap may cause the spark to wait forever.
Also, this may affect the quality of the spark in terms of its ability to start a good burn.
You are correct on both accounts.
However.. changing the spark plug gap to tune the timing is not the best or sometimes correct way to go about it.
The spark plug gap should be set up for best overall performance and burn needs of the engine covering the entire range of RPM's and loads encountered.
Let the ignition system do it's job of controlling when the spark occurs.
Note: spark plug gap also affects it's heat saturation, you can affect a spark plug to operate hotter by opening up the gap a little. Closing it will cause it to run a little cooler. This can help tune the operating heat range of the spark plug to be more or less resistant to fouling or overheating.